Machine for producing thin section specimens

ABSTRACT

A versatile apparatus for both cutting and grinding, lapping and polishing solid material to produce thin section specimens for analysis and quality control is disclosed herein and includes a support base upon which a quill assembly is mounted. The quill assembly is provided for imparting longitudinal movement to a power-driven rotationally movable spindle, grinding wheel, and cutting wheel, the latter two being connected with the spindle for rotational movement therewith. In this regard, the apparatus includes a differential screw and annular micrometer dial for effecting accurate longitudinal adjustment of the spindle. A sliding cross-plate is also mounted on the aforestated support base and is designed to be manually moved both toward and away from the grinding and cutting wheels. A specimen holder removably mounted on the sliding cross plate is designed to bring a pair of spaced apart specimens into contacting engagement with the wheels whereby one of the specimens will be in contacting engagement with a corresponding one of said wheels when the cross plate is moved toward the latter.

; tet 1 [111 3,828,75 Aug. 13, 19741 1 MACHINE F OR PRODUCING THINSECTION SPECIMENS [76] Inventor: Paul 0. Cary, 423 E. Mayfield Dr.,

Grand Junction, Colo. 81501 22 Filed: Sept. 27, 1972 21 Appl.No.:292,847

[52] 11.8. CI. 125/13 R, 51/3, 51/166 MI-I Primary Examiner-Harold D.Whitehead Attorney, Agent, or Firm-Burton, Crandell, Polumbus & Harris[5 7] STRACT A versatile apparatus for both cutting and grinding,lapping and polishing solid material to produce thin section specimensfor analysis and quality control is disclosed herein and includes asupport base upon which a quill assembly is mounted. The quill assemblyis provided for imparting longitudinal movement to a power-drivenrotationally movable spindle, grinding wheel, and cutting wheel, thelatter two being connected with the spindle for rotational movementtherewith. In this regard, the apparatus includes a differential screwand annular micrometer dial for effecting accurate longitudinaladjustment of the spindle. A sliding cross-plate is also mounted on theaforestated support base and is designed 'to be manually moved bothtoward and away from the grinding and cutting wheels. A specimen holderremovably mounted on the sliding cross plate is designed to bring a pairof spaced apart specimens into contacting engagement with the wheelswhereby one of the specimens will be in contacting engagement with acorresponding one of said wheels when the cross plate is moved towardthe latter.

11 Claims, 6 Drawing Figures MACHINE FOR PRODUCING THIN SECTIONSPECIMENS BACKGROUND OF THE INVENTION 1. Field of the Invention Thepresent invention relates generally to an apparatus for producingobjects of predetermined design and more particularly to an apparatusfor producing thin section specimens.

2. Description of the Prior Art To date, as well as in the past,machines are being utilized to process solid material for purposes ofanalysis, quality control and/or production of products. For example, inthe processing of ore, thin section specimens are produced and used bymineralogists and geologists to determine the mineral content and grainstructure of any given sample. In many cases, such specimens mustpossess certain physical characteristics which will render them useful.For example, they must be very thin, normally about 30 microns thick,and must be in a plane as nearly parallel to the surface of a glassslide as possible. It is usually very desirable that the surface of suchspecimens be as smooth as possible and polishing is often necessary toobtain this feature.

In the past, the conventional way of producing such specimens, asheretofore practiced, is to clamp the initial lump of material fromwhich the specimen is to be taken in a large slabbing saw well known inthe art and in wide use. A cut is taken through the lump of material toestablish a flat surface, then the lump is reclamped and a second cuttaken in order to provide a relatively thin section or slab having tworoughly parallel faces. From this relatively thin slab, a specimen iscut that will suitably fit upon a glass slide.

The specimen is then placed upon a lapping plate and one side is lappedto obtain a smooth, flat surface, the lapped surface being impregnatedwith a suitable bonding agent and then bonded to the glass slide. Thespecimen, now mounted upon the slide, goes through subsequent trimming,lapping, and polishing operations, in order to obtain the finishedspecimen. These subsequent operations, as heretofore practiced, haveinvolved the use of various different machines or devices for eachoperation, for instance, a small slabbing saw for trimming, a lapping orgrinding machine and a polishing machine. It should be readily apparentthat the employment of these various differnt means involves a greatdeal of operator time and skill because the specimens are, for the mostpart, clamped, trimmed, fed, lapped or ground, and polished by hand.Skill on the part of the operator is very important because the operatormust correct any errors induced in prior operations.

Since specimens are usually worked through the abovementioned operationsby hand and through different machines, the heretofore practiced processdoes not lend itself very well when the time it takes to produce suchspecimens is an important factor. In this regard, the requiredproduction of such specimens has been continuously increasing, due toincreased research in various activities. Therefore, the required timeto obtain the finished specimen and, hence, the analysis has become moreimportant.

Many of the foregoing deficiencies have been overcome by a more recentapparatus which is disclosed in United States Letters Pat. No. 3,467,075issued to Paul O. Cary, applicant of the present invention. Morespecifically, the Cary patent discloses a hand operated sectioningmachine including a quill assembly which cooperates with a single threadmovement control arrangement for longitudinally moving a power drivenspindle in a controlled fashion. The spindle, in turn, rotatably driveseither the specimen cutting blade adapted to provide thin specimensections or a grinding wheel adapted to grind and polish the thinsection or slab to final thickness. In this regard, the apparatus of theCary patent also includes a cross slide supporting a single specimenvacuum chuck, both of which are adapted for manual movement transverseto the longitudinal movement of the spindle. In this manner, a singlespecimen can be affixed to the vacuum chuck and alternatively workedupon by either the cutter blade or grinding wheel.

As will be seen hereinafter, the present invention among other features,provides a novel quill assembly and cooperating spindle controlarrangement as well as the spindle, cross slide and specimen holdingvacuum chuck. For example, longitudinal movement of the spindle iscontrolled by a Micrometer dial utilizing a differential screwarrangement rather than the single thread arrangement disclosed in theCary patent. This, in turn, results in much finer movement control ofthe spindle without the disadvantages of extremely fine threads. Onefull turn of the micrometer dial results in a very small lateralmovement of the wheel assembly and therefore a very small longitudinalmovement of the spindle. Hence, very fine control over the amount ofmaterial being removed from the specimen section during either cuttingor grinding can be achieved.

In addition, the present invention provides a visual dial indicatorwhich accurately shows movement of the quill assembly, resulting in anaccurate method of monitoring the amount of material being removed fromthe specimen section. Further, it has been found that themicrometer-quill assembly is less complicated and more economical tomanufacture than the earlier quill assembly described in the Carypatent.

Another novel feature of the present invention over the Cary patentresides in the utilization of two specimen treating means such as acutting blade and a grinding wheel mounted adjacent each other on oneend of the same spindle. Hence, while one specimen may be trimmed into athin section, a second specimen can be simultaneously held and broughtinto position for the subsequent grinding operation. In this regard, thepresent invention also provides a dual vacuum chuck adapted to supporttwo specimens simultaneously. The dual vacuum chuck is mounted on anovel cross slide which straddles the two working wheels and hence ismore stable during movement transverse to the wheels.

From the foregoing and, as will be more apparent hereinafter, theutilization of a micrometer including a differential screw, aquill-spindle arrangement including the simultaneous use of two specimentreating means and a visual dial indicator, and a dual vacuum chuckmounted on a cross slide which straddles the two specimen treating meansresults in a novel arrangement which is more versatile and efficient,and more practical and easier to operate than previous apparatusutilized for the same basic purpose. In this regard, other novelfeatures of the present invention over tbe apparatus disclosed in theCary patent as well as other apparatus'of the prior art will becomeapparent hereinafter.

OBJECTS OF THE INVENTION In accordance with the foregoing, an object ofthe present invention is to provide a novel apparatus for producing thinsection specimens on a large scale production basis.

Another object of the present invention is to provide a novel apparatusfor surfacing, trimming, grinding, lapping, and polishing thin sectionspecimens.

Another object of the present invention is to provide a novel apparatusfor producing and working on more than one specimen simultaneously.

Another object of the present invention is to provide an apparatus forproducing thin section specimens including a novel arrangement forcontrolling the amount of movement of the various moving parts of theapparatus.

Another object of the present invention is to provide an apparatus fortrimming or cutting one specimen and simultaneously holding a secondpreviously trimmed specimen so that said second specimen can beimmediately ground upon completion of the trimming.

Another object of the present invention is to provide an apparatus forproducing thin section specimens including a novel specimen holdingassembly especially suitable for simultaneously holding two specimens atone time.

Another object of the present invention is to provide a specimen holdingassembly of the last mentioned type which is more stable during movementof the specimens than heretofore provided.

Another object of the present invention is to provide an improvedapparatus for producing thin section specimens including improved meansfor accurately monitoring the amount of material being removed duringoperation of the apparatus.

Another object of the present invention is to provide a thin sectionspecimen producing apparatus which is more versatile and efficient, morepractical, and less complicated to operate than heretofore provided.

These and other objects and features of the present invention becomeapparent from the following descriptrons.

DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. I is a plan view of the thin section specimen producing apparatusconstructed in accordance with the present invention;

FIG. 2 is a front elevational view of the apparatus of FIG. 1;

FIG. 3 is a right end elevational view of the apparatus of FIG. 1;

FIG. 4 is a sectional view taken through the dual vacuum chuck alongline 44 in FIG. 3;

FIG. 5 is a sectional view taken generally along line 55 in FIG. 3; and

FIG. 6 is a sectional view similar to FIG. 5 and showing a modifiedmeans for sensing longitudinal movement of the specimen treating means.

DETAILED DESCRIPTION Turning now to the drawings, wherein likecomponents are designated by like reference numerals throughout thevarious figures, a thin section specimen producing apparatus,constructed in accordance with the present invention, is illustrated andgenerally designated by the reference numeral 10. As will be describedin more detail hereinafter, apparatus 10 includes a support base 12 uponwhich a quill assembly 14 is mounted. As will also be seen hereinafter,the quill assembly 14 includes a housing 16 and a quill 18 (see FIG. 5)mounted within the housing 16 for longitudinal, non-rotary movementrelative thereto.

Mounted within quill 18 is a rotational system 20 (see FIG. 5) includinga spindle 22 adaptable to rotational movement and a pair oflongitudinally spaced apart specimen treating members 24 and 26 mountedon the spindle adjacent one end thereof. As will be seen hereafter, thespecimen treating members 24 and 26 will generally be a grinding wheeland cutting wheel, respectively, both of which are keyed for rotationwith spindle 22. In this regard, a power assembly 28 also mounted tosupport base 12 and positioned adjacent rotational system 20 is designedto transmit rotational power to the spindle 22.

Apparatus 10 further includes a sliding cross plate arrangement (bestillustrated in FIG. 3) which is mounted on the support base and designedto be moved, preferably manually, both toward and away from the specimentreating members 24 and 26. The specimen holder 32 is removably mountedon the sliding cross plate and designed to bring a pair of spaced apartspecimens into contacting engagement with the spaced apart treatingmembers 24 and 26. Hence, while one specimen will be brought intocontacting engagement with the cutting wheel 26, a secnd specimen may besimultaneously held and brought into position for a subsequent grindingoperation with grinding wheel 24. This, of course, eliminates thealternate mounting of the grinding wheel and blade required in previousdesigns. In addition, this dual system, as will be seen hereinafter,allows the sliding cross plate to be positioned in a straddling fashionwith respect to the two treating members, thereby providing a morestable sliding cross plate.

In another mode of operation where specimen treating means 24 isreplaced with a cutting blade, it is then possible to treatsimultaneously two specimens when the sliding cross plate is movedtoward the otat onal system. In this regard, as will be seenhereinafter, the specimen holder is comprised of a dual vacuum chuckarrangement adapted to hold more reliably both specimens in place.

In order to control the amount of material removed from the specimens,the entire quill 18 is adjusted longitudinally which, in turn, adjuststhe entire rotational system 20 including spindle 22 and specimentreating members 24 and 26 longitudinally. As will be seen hereinafter,this is achieved in a more accurate and less complicated fashion by theutilization of a novel quill movement control arrangement 34 including adifferential screw arrangement 36, an annular micrometer dial 38, bothof which cooperate with the quill 18 to provide longitudinal movement ofthe latter. By providing the novel arrangement of differential screw andmicrometer dial, a much finer adjustment of the spindle and specimentreating members can be achieved. One full turn of the micrometer dial38 results in a very precise control over the amount of material beingremoved from the thin section and achieves an increased degree ofaccuracy over the thickness of the finished product. In order to furtherenhance accuracy of spindle movement, apparatus 10 includes a visualdial indicator 40 (see FIG. 5) which indicates the amount of movement ofquill l8.

Turning now to the details of apparatus 10, attention is redirected tosupport base 12 which, as illustrated best in FIGS. 1 and 2, includes aplurality of vertically disposed support panels 42 suitablyinterconnected together and mounted on rubber feet 44, the latter beingprovided to compensate for any unevenness of surface and also to resistslippage. The support base 12 also includes a coolant drain floor 46which comprises the front portion of the base and a control panel 48 andadjacent mounting deck 50 which together form the rear portion of base12. The farious components comprising the support base 12 as well asmany of those components mounted to the base are preferably weldedtogether, but may be joined by any other suitable geans, includingbolts. A flap door (not shown) maybe provided on the front side of thebase for allowing easy access to the area beneath drain floor 46. Sucharea contains a pull-out coolant tray and a recirculating cooling pumpsystem.

Turning to FIGS. 1, 2 and 5, attention is now directed to quill assembly14 which, as illustrated, includes cylindrical housing 16 which ismounted to deck 50 by a suitable mounting block 52. A plurality ofopenings 53 are provided through the housing for lubricating thecomponents therein. Within each end of the quill housing are two sleevebearings 54 which circumscribe quill 18, the latter being concentricallypositioned within housing 16 so as to bear against the inner face ofeach sleeve bearing. The quill includes near its rearward or lefthandend, as viewed in FIG. 5, external threads 56 which, as will be seenhereinafter, cooperate with movement control arrangement 34 andparticularly differential screw 36.

Quill 18 is prevented from rotational movement by an anvil stud 58 whichscrews into the outer diameter of the quill and fits in a longitudinalslot 78 cut into the quill housing, thereby alolowing longitudinalmovement of the quill but preventing rotational movement thereof. Aswill be seen hereinafter, this anvil stud also transmits thelongitudinal movement of the quill, and therefore longitudinal movementof the spindle, to dial indicator 40. Thus, the anvil stud serves a twofold purpose, i.e., to cooperate with the dial indicator 40 to give aread out on longitudinal spindle movement and also to prevent rotationalmovement of the quill, this arrangement being a notable advancement overthe previously described Cary patent.

In accordance with the present invention, movement control arrangement34 includes the aforestated differential screw 36 which, as will be seenhereinafter, provides extremely accurate longitudinal adjustment of thequill l8 and therefore, spindle 22. The differential screw 36 includesan annular member 60 which is internally threaded at 62 and externallythreaded at 64, the external threads differing in pitch from the pitchof the internal threads. in fact, in accordance with a preferredembodiment of the present invention, the external threads 64 display apitch of 28 while the internal threads 62 display a pitch of 36, therebyproviding an external to internal pitch ratio of 7/9. As illustrated inFIG. 5, annular member 60 is positioned concentrically around'quill 18so that internal threads 62 are disposed in complementary threadedengagement with the external threads 56 of the latter.

Differential screw 36 further includes a second annular member 66 whichis greater in diameter than annular member 60 and which qs suitablyfixed to the inner surface of quill housing 16. Annular member 66 isinternally threaded at 68, the internal threads being disposed incomplementary threaded engagement with the external threads 64- ofannular member 60. Micrometer dial 38 which, in essence, comprises partof differnetial screw 36 that is included in movement controlarrangement 34, is annular in configuration. The micrometer dial isfixed to and circumscribes previously described annular member 60 forimporting axial rotational movement to the latter in response torotational movement of the micrometer dial. In this regard, asillustrated in FIG. 1 and FIG. 2, the micrometer dial includes numerousgraduations 70 engraved around its circumference which are easily set inrelation to a witness mark 72 (see FIG. 2), thus closely controllinglongitudinal movement scale 74, as will be seen hereinafter.

From the foregoing, it should be readily apparent that by movingmicrometer dial 38, and therefore annular member 60, extremely fine andaccurate longitudinal movement of quill 18 is achieved. For example, byutilizing an external to internal thread pitch of 7/9 for annular member60, the net movement of quill 18 in a working embodiment of the presentinvention has been found to be approximately 0.008 inches per revolutionon micrometer dial 38. In this working embodiment, the dial 38 has 200equal graduations resulting in a 0.00004 inch wheel travel pergraduation. This also equals 1 micron in metric measurement. However, itis to be understood that the present invention is not limited to thisspecific arrangement but may be provided with either coarser or fineradjustment depending, of course, on the pitch arrangement of thedifferential screw.

It should be noted that because of the utilization of differential screw36, an unlocking screw similar to that utilized in the aforedescribedCary patent is not necessary in the present invention to secure quill 18against longitudinal movement. This is primarily due to the inherentability of the differential screw to hold its adjustment and, in actualuse, the screw is constantly being operated to move the specimentreating members to be described ereinafter, into contacting engagementwith a specimen in order to remove material. When the differential screwis used to move the quill forward, the screw threads back each other upat zero clearance and when reversing this procedure, back lash due tothe normal clearance in the threads is eliminated by the use of ananti-backlash spring (compression spring) to be described hereinafter.This spring provides continuous urging or pulling of the wheel anddifferential screw assembly in a direction away from the specimentreating members to keep the thread clearances at zero and therebyeliminating backlash, thereby providing more accurate readings on thedial indicator.

As stated hereinabove, apparatus 10 also includes an indicator40provided for sensing and accurately visually indicating the relativeamount of longitudinal movement of quill 18. To accomplish this,indicator 40 includes-a scale 74 and indicating means 76 and a sensordisposed in contacting engagement with the previously described anvilstud 58. Since the anvil stud 58 is attached to the quill 18, movementof the quill 18 is transmitted through the stud 58 to the sensor and, inturn, to the indicating means 76.

Attention is now directed to rotation system which, as stated above,includes spindle 22. As illustrated in FIG. 5, the spindle 22 isrotatably journaled inside quill 18 and runs in a plurality of ballbearings 80. The spindle has a pair of longitudinally spaced mountingflange spacers 82 and 84 and a threaded thrust coller 86, both acting toretain the spindle longitudinally and to preload the bearings 80 inorder to eliminate spindle end shake. The thrust collar 86 is threadablyengaged with the spindle and provides a manner of adjusting the amountof bearing preload. In addition, the mounting flanges 82 and 84 providesuitable surfaces for respectively mounting specimen treating members 24and 26. In this regard, the treating members are retained in the flangesby a washer 88 and screw 90.

Extending from the spindle 22 out of the quill 18 is a drive rod 92which preferably displays a square crosssection. The drive rod engages asquare hole in a pulley 94 which is rotatably journaled in a ballbearing 96 so that the pulley is free to turn, but longitudinallyretained. Ball bearings 96 is mounted in a housing 98 which is suitablymounted on deck 50. Hence, it should be clear that, since pulley 94engages the square drive rod with a square hole, a means is provided forthe pulley to transmit rotary power to the spindle 22 and at the sametime allowing the spindle to be longitudinally moved in relation to thepulley. It should also be clear that, by rotating the pulley andtherefore the spindle, the mounting flanges and therefore specimentreating members 24 and 26 are rotated. It should be noted that theanti-backlash spring providing the aforedescribed function is positionedaround the free end of drive rod 92 between pulley 94 and a flangeelement 100 fixed to the end of the drive rod.

Returning to FIGS. 1 and 2, attention is re-directed to power assembly28 which, as illustrated, includes a suitable drive motor 102 mounted todeck 50. The drive motor includes a pulley 104 and a V-belt 106 betweenpulleys 94 and 104 to provide a transfer of power. A belt guard 108 maybe provided for safety considerations.

As illustrated in FIGS. 1 to 3, the sliding cross plate assembly 30 ismounted on the coolant drain floor 46 and includes a cross slide base110. At each end of base 110 are positioned shaft mounting blocks 112 inwhich are mounted two parallel shafts 114. A cross slide plate 116 ismounted upon shafts 114 utilizing ball bushings 118 for linear movement.Hence, the slide plate 116 is capable of sliding along the length of theshafts under a very small amount of applied pressure.

In accordance with another feature of the present invention, a dualvacuum chuck 120 is mounted upon the cross slide plate 116, the oppositefaces 122 and 124 of which are employed to hold microscope slides towhich have been mounted suitable specimens. As illustrated best in FIG.4, a vacuum is supplied to the chuck from a conventional source (notshown) through a suitable conduit (not shown) and thereafter by a centerport or passage 126 provided centrally in the chuck. The center port 126is, in turn, in communication with two main parts or passages 128 and130, each of the latter being in respective communication with aplurality of surface ports or passages 132 and 134 extending,respectively, to opposite faces 122 and 124. While the dual vacuum chuckis a preferred arrangement for supporting two specimens, it is to beunderstood that the present invention is not limited to this particulararrangement.

From the foregoing, it should be noted that the cross slide plate 116straddles the specimen treating member 24, which as states hereinabovecan be a grinding plate, and specimen treating member 26, which can be acutting blade, for providing a more stable arrangement. In addition, thecross slide plate allows for the use of the dual vacuum chuck.

The cross slide assembly can also be used for mounting attachments suchas, for example, a rock vise, a collect attachment for holding rockcores or a polishing holder. In addition, the cutting blade can beremoved and the grinding plate can be used for hand lapping or thegrinding plate can be replaced with polishing plates for final polishingoperations with very fine polishing abrasures, compounds, and the like.Removal of the cutting blade enables the grinding or polishing plates tobe easily used from the front during this handwork. The above handgrinding is usually done after having a flat surface on the rock whichis held in the rock vise or collet attachment and prior to bonding therock to a glass microscope slide. The polishing'is done usually afterthe thin section has been ground to final thickness. It should bepointed out, however, that lapping and polishing can also be done withthe specimen held by the vacuum chuck or other type of specimen holders.

Referring to FIGS. 1 to 3, it is to be noted that a handle 140 isprovided for hand feeding the cross plate towards the specimen treatingmembers 24 and 26 during operation of apparatus 10. An auxiliary finefeeding lever 142 is provided for more closely controlled feeding of thecross slide plate and greater leverage. In this regard, the lever 142includes a lever block 144 which is pivotally mounted at its lower endto the cross slide base by a pivot screw 146 and a spacer block 148.Pivot screw 146 threads into the cross slide base. The hole in thespacer 148 and the lever block 144 are clearance holes. Hence, it shouldbe obvious that the lever 142 can be moved in an arc.

Attached to the cross slide 116 is a stud 150 on which is mounted a ballbearing 152. The ball bearing 152 engages a slot 154 milled in block144. The width of slot 154 closely fits the diameter of ball bearing152. It can be seen that, when the feed lever 142 is removed in its arc,motion is transmitted from the lever block 144 to the cross slide plate116 by means of the slot 154 and ball bearings 152, the movement of thecross slide being parallel to the axis of shafts 114.

The apparatus of this invention may also include a spray coolant system(not shown) since spraying lengthens the life of the cutting mechanismby facilitating its work. Spraying also enhances the finished product.Such a spraying system would be similar to that shown in the aforestatedCary patent.

In FIG. 6 is shown a modification of the structure illustrated in FIG.5. FIG. 6 depicts a different means for sensing longitudinal movement ofthe specimen treating means particularly the grindind wheel 24. As shownin FIG. 6, the housing 16 has a longitudinally extending opening 158formed through a portion thereof. One end 160 of said opening 158 isformed with an increased diameter. A sensor rod 162 is mounted forreciprocal movement within the opening 158 and is biased toward theadjacent face of the grinding wheel 24 by a compression spring 164. Thesensor rod 162 has a head or flange 166 formed on one end thereof and isdisposed to abuttingly engage an L-shaped member 168. The L-shapedmember 168 is suitably connected to the dial indicator 40 from which maybe ascertained the amount of longitudinal movement of the grinding wheel24. As shown, the sensor rod 162 also includes a flange or boss 170formed adjacent the other end thereof and against which is seated oneend of the compression spring 164. The end of the rod 162 in contactwith the wheel 24' is preferably arcuate or rounded in configuration.The left end of the sensor rod 162 and its flange 166 is shown in dottedlines for a position associated with a retraction of the grinding wheel24. It will be appreciated that longitudinal movement of the cuttingblade 26 will likewise be ascertained in the same manner since thegrinding wheel 24 and cutting blade 26 are held in rigid spaced-apartrelationship by suitable mounting thereof upon the spindle 22.

The operation of the machine is as follows: In place of the dual vacuumchuck 120, a vise (not illustrated) may be mounted on the cross slide.With the machine set up rocks can be cut into slabs by feeding them pastthe saw blade. In this case, the handle 142 is used in order to feed therocks smoothly and so the operator can easily control the rate of feed.As many rock slabs as necessary can be run through this first surfaceoperation.

After all the rocks have been slabbed, the first surfaces are lappedflat and then respectively bonded to glass microscope slides. The viseis removed and the dual vacuum chuck 120 is mounted on the cross slideplate 116.

Referring to FIGS. 2 and 4, a blank glass microscope slide is fixed tothe left side 122 of the specimen holder 32 and a glass slide with aspecimen mounted thereon is fixed to the right side 124. The quill 18 isadjusted longitudinally to position the specimen treating means 24,which in this case is a grinding wheel, and treating means 26, which isa cutting blade, so there is more clearance between the treating face ofthe grinding wheel 24 and the left side 122 of the specimen holder thanthere is between the right side 124 of the specimen holder and theinside cutting edge of the blade 26.

The power assembly 28 is energized by suitable control means (not shown)for transmitting rotational power to the spindle 22 and thereforespecimen treating members 24 and 26. Thereafter, the sliding crossplate, specimen holder and specimens are moved toward the specimentreating means. However, only the mounted specimen is brought intocontacting engagement with the blade 26 since the other side of thespecimen holder 32 holds only a blank side and because of the increasedclearance existing between the left side 122 and its correspondinggrinding wheel 24. The sliding cross plate and specimen holder isadvanced past the cutting edge of the blade 26 leaving a relatively thinsection of specimen material remaining on the glass slide. The slidingcross plate is then moved away from the specimen treating means to clearthe trimmed specimen.

The blank microscope olide (which is used to close off the openingformed within the vacuum chuck) is then removed from the left side ofthe specimen holder (as viewed in FIG. 1) and replaced by the blank uponwhich is mounted the thin section specimen just trimmed. A secondmounted specimen is fixed to the right side of the specimen holder andthe trimming operation is repeated thus producing a second trimmed thinsection specimen. While trimming the second specimen, the first one, onthe opposite side 122 of the specimen holder, is not touched bytreagiting means 24 in view of the aforementioned greater clearance onthat side. However, immediately after the second section is trimmed thequill l8 and, therefore, the grinding wheel 24, is adjustedlongitudinally to bring the treating face of the grinding wheel 24 intocontacting engagement with the thin section on the left side of thespecimen holder. Thus, the grinding operation may now proceed. Duringgrinding, the sliding cross plate is moved back and forth thus passingthe thin section across the treating face of the grinding wheel 24 andat the same time the quill 18 and therefore the grinding wheel 24 ismoved gradually against the thin section specimen in order to grind itto a final thickness. It is well to note that while the grinding wheel24 is being advanced toward its corresponding thin section specimen, theblade 26 is continually moving away from its corresponding specimenthereby eliminating serrating or scarring the previously trimmedsection. When the first thin section specimen has been finished groundthe quill 18 and specimen treating means 24 and 26 are repositioned fortrimming another mounted specimen. The finished thin section is removedfrom the holder 32 and replaced by the trimmed section from the rightside of the specimen holder, another mounted specimen is fixed to theright side 124 and the whol above sequence of operations is repeated(alternating between trimming the mounted specimens and grinding thethin sections). It can be seen that small numbers of finished thinsections can be obtained quickly using the above procedure. However,when specimens are sectioned in large numbers it is understood that theycan be produced by setting the machine for the trimming operation andrunning all specimens through the trimming operation and then proceed togrind all specimens in a separate grinding operation. It will beunderstood that if the specimen treating means 24 and 26 comprise twocutting blades, then mounted specimens can be trimmed on both sides ofthe specimen holder 32 simultaneously during one operation.

In view of the foregoing, it will be readily appreciated that a noveland versatile machine for producing thin section specimens has beendescribed. The machine of this invention includes a novel quill assemblyand cooperating spindle control arrangement as well as a spindle, crossslide and specimen holding vacuum chuck. Accurate longitudinal movementof the spindle is maintained at all times through the use of adifferential screw arrangement in lieu of extremely fine threads. Aplurality of specimens may be treated simultaneously with the machine ofthis invention thereby increasing the rate of production and decreasingthe cost for producing each specimen. On the other hand, if only a fewspecimens are required, it can be quickly done because the dual vacuumchuck with the grinding wheel and the cutting blade can be utilizedwithout having to set the machine up for either the grinding or sawingoperation.

It is to be understood that this invention is not limited to the exactembodiment of the machine described and shown which is merely by way ofillustration and not limitation, as various other forms andmodifications will be apparent to those skilled in the art.

I claim: 1. A machine for producing thin section specimens comprising:

a. a support base;

b. a quill housing mounted on said base;

c. a quill mounted within said housing for longitudinal, non-rotarymovement relative thereto;

d. a rotational system mounted within said quill, said system having aspindle adaptable to rotational movement, and a pair of longitudinallyspacedapart specimen treating means mounted on said spindle adjacent oneend thereof;

e. a power means mounted on said support base adjacent said rotationalsystem and designed to transmit rotational power to said spindle;

f. a sliding cross slide plate mounted on said support base and designedto be moved both toward and away from the specimen treating means ofsaid rotational system;

g. a specimen holder removably mounted on said cross slide plate anddesigned to bring a pair of spaced-apart specimens into contactingengagement with said spaced-apart treating means whereby one of saidspecimens will be in contacting engagement with a corresponding one ofsaid treating means when said cross slide plate is moved toward saidrotational system;

h. means for effecting accurate longitudinal adjustment of said spindle,said means comprising a differential screw, said screw having internallyand externally threaded portions, the lead of said externally threadedportion being different than the lead of said internally threadedportion, and including (i) an annular micrometer dial, (ii) said quillhousing having fixed internal threads, the internal threads of saidquill housing being disposed in complemental engagement with theexternal threads of said differential screw, and (iii) a portion of saidquill including an externally threaded portion, the external threads ofsaid quill being disposed in complemental engagement with the internalthreads of said differential screw; and

i. means for sensing and accurately indicating the relative amount oflongitudinal movement of said spindle, said means including (i) a firstpart secured to said quill housing and including an indicating memberand a scale means, and (ii) a second part one portion of which isdisposed to transmit longitudinal movement of said specimen treatingmeans to the indicating means of said first part.

2. A machine as described in claim 1 above in which said specimen holderincludes a pair of spaced-apart surfaces disposed generally parallel oneto the other, each surface including one or more means, each of saidmeans constructed to receive one specimen.

3. A machine as described in claim 2 above in which a portion of eachspaced-apart surface of said specimen holder, upon movement of saidcross slide plate toward the specimen treating means, is disposedintermediate said specimen treating means.

4. A machine as described in claim 3 above in which one of said specimentreating means includes a cutter blade and the other one of saidspecimen treating means includes a surface grinder.

5. A machine as described in claim 4 above in which each of the means ofthe spaced-apart surfaces of said specimen holder is constructed to bedisposed in fluid communication with a source of vacuum pressure, andmeans to provide a vacuum pressure to each of said means whereby, uponpositioning of specimens on said means and furnishing vacuum pressure tosaid specimen holder, said specimens will be held upon said specimenholder.

6. In a machine for producing thin section specimens, said machineincluding a support base, a quill housing mounted on said base, a quillmounted within said housing for longitudinal, non-rotary movementrelative thereto, and a rotational system mounted in said quill andincluding a spindle adapted for rotational movement within said quill,the improvement comprising:

a. a pair of longitudinally spaced-apart specimen treating means mountedon said spindle adjacent one end thereof;

b. a sliding cross slide plate mounted on said support base and designedto be moved both toward and away from said specimen treating means;

0. a specimen holder removably mounted on said cross slide plate anddesigned to bring one or more specimens into contacting engagement withsaid specimen treating means; and

d. means for effecting accurate longitudinal movement of said spindle,said means comprising a differential screw having a first annular memberwith internally and externally threaded portions, the lead of saidexternally threaded portion being different than the lead of saidinternally threaded portion and a second member with an internallythreaded portion, the internal threads of said second member beingdisposed in complimental engagement with the external threads of saidfirst member, and a portion of said quill being externally threaded, theexternal threads of said quill being disposed in complimental engagementwith the internal threads of said first member, and said differentialscrew also including an annular dial means mounted for rotationalmovement with said first member.

7. In a machine for producing thin section specimens, said machineincluding a support base, a quill housing mounted on said base, a quillmounted within said housing for longitudinal, non-rotary movementrelative thereto, and a rotational system mounted in said quill andincluding a spindle adapted for rotational movement within said quill,the improvement comprising:

a. a pair of longitudinally spaced-apart specimen treating means mountedon said spindle adjacent one end thereof;

b. a sliding cross slide plate mounted on said support base and designedto be moved both toward and away from said specimen treating means;

0. a specimen holder removably mounted on said cross slide plate anddesigned to bring one or more specimens into contacting engagement withsaid specimen treating means; and

d. means for effecting accurate longitudinal movement of said spindle,said means comprising a differential screw having a first annular memberwith internally and externally threaded portions, the lead of saidexternally threaded portion being different from the lead of saidinternally threaded portion, a portion of said gull housing beinginternally threaded, the internal threads of said quill housing beingdisposed in complemental engagement with the external threads of saidfirst member, and a portion of said quill being externally threaded, theexternal threads of said quill being disposed in complemental engagementwith the internal threads of said first member, and said differentialscrew also including an annular dial means mounted for rotationalmovement with said first member.

8. In a machine as described in claim 6 above in which said secondmember is mounted on said quill housing.

9. In a machine as described in claim 6 above including means forsensing and indicating the relative amount of longitudinal movement ofsaid spindle, said means including a first part secured to said quillhousing and including an indicating member and a scale member, and asecond part one portion of which is disposed to transmit longitudinalmovement of said spindle to the indicating means of said first part.

10. In a machine as described in claim 6 above including means forsensing and indicating the relative amount of longitudinal movement ofthe specimen treating means, said means including a first part securedto said quill housing and including an indicating member and a scalemember, and a second part comprising a sensor rod mounted within saidquill housing for reciprocal movement relative thereto, said sensor rodbeing biased in a direction toward an adjacent surface of said specimentreating means, said sensor rod having a portion thereof disposed inmotion transmitting engagement with the indicating means of said firstpart whereby longitudinal movement of said specimen treating means maybe transmitted to the indicating member of said first part.

ll. A machine for producing thin section specimens comprising:

a. a support base;

b. a quill housing mounted on said base;

0. a quill mounted within said housing for longitudinal, non-rotarymovement relative thereto;

d. a rotational system mounted within said quill, said system having aspindle adaptable to rotational movement, and a pair of longitudinallyspacedapart specimen treating means mounted on said spindle adjacent oneend thereof;

e. a power means mounted on said support base adjacent said rotationalsystem and designed to transmit rotational power to said spindle;

a sliding cross slide plate mounted on said support base and designed tobe moved both toward and away from the specimen treating means of saidrotational system;

g. a specimen holder removably mounted on said cross-slide plate anddesigned to bring one or more specimens into contacting engagement withsaid specimen treating means when said cross slide plate is moved towardsaid rotational system;

h. means for effecting accurate longitudinal adjustment of said spindle,said means comprising a differential screw, said screw having internallyand externally threaded portions, the lead of said externally threadedportion being different than the lead of said internally threadedportion, and including (i) an annular micrometer dial, (ii) said quillhousing having fixed internal threads, the internal threads of saidquill housing being disposed in complemental engagement with theexternal threads of said differential screw, and (iii) a portion of saidquill including an externally threaded portion, the external threads ofsaid quill being disposed in complemental engagement with the internalthreads of said differential screw; and

i. means for sensing and accurately indicating the relative amount oflongitudinal movement of said spindle, said means including (i) a firstpart secured to said quill housing and including an indicating memberand a scale means, and (ii) a second part one portion of which isdisposed to transmit longitudinal movement of said specimen treatingmeans to the indicating means of said first part.

* =l l l l=

1. A machine for producing thin section specimens comprising: a. asupport base; b. a quill housing mounted on said base; c. a quillmounted within said housing for longItudinal, nonrotary movementrelative thereto; d. a rotational system mounted within said quill, saidsystem having a spindle adaptable to rotational movement, and a pair oflongitudinally spaced-apart specimen treating means mounted on saidspindle adjacent one end thereof; e. a power means mounted on saidsupport base adjacent said rotational system and designed to transmitrotational power to said spindle; f. a sliding cross slide plate mountedon said support base and designed to be moved both toward and away fromthe specimen treating means of said rotational system; g. a specimenholder removably mounted on said cross slide plate and designed to bringa pair of spaced-apart specimens into contacting engagement with saidspaced-apart treating means whereby one of said specimens will be incontacting engagement with a corresponding one of said treating meanswhen said cross slide plate is moved toward said rotational system; h.means for effecting accurate longitudinal adjustment of said spindle,said means comprising a differential screw, said screw having internallyand externally threaded portions, the lead of said externally threadedportion being different than the lead of said internally threadedportion, and including (i) an annular micrometer dial, (ii) said quillhousing having fixed internal threads, the internal threads of saidquill housing being disposed in complemental engagement with theexternal threads of said differential screw, and (iii) a portion of saidquill including an externally threaded portion, the external threads ofsaid quill being disposed in complemental engagement with the internalthreads of said differential screw; and i. means for sensing andaccurately indicating the relative amount of longitudinal movement ofsaid spindle, said means including (i) a first part secured to saidquill housing and including an indicating member and a scale means, and(ii) a second part one portion of which is disposed to transmitlongitudinal movement of said specimen treating means to the indicatingmeans of said first part.
 2. A machine as described in claim 1 above inwhich said specimen holder includes a pair of spaced-apart surfacesdisposed generally parallel one to the other, each surface including oneor more means, each of said means constructed to receive one specimen.3. A machine as described in claim 2 above in which a portion of eachspaced-apart surface of said specimen holder, upon movement of saidcross slide plate toward the specimen treating means, is disposedintermediate said specimen treating means.
 4. A machine as described inclaim 3 above in which one of said specimen treating means includes acutter blade and the other one of said specimen treating means includesa surface grinder.
 5. A machine as described in claim 4 above in whicheach of the means of the spaced-apart surfaces of said specimen holderis constructed to be disposed in fluid communication with a source ofvacuum pressure, and means to provide a vacuum pressure to each of saidmeans whereby, upon positioning of specimens on said means andfurnishing vacuum pressure to said specimen holder, said specimens willbe held upon said specimen holder.
 6. In a machine for producing thinsection specimens, said machine including a support base, a quillhousing mounted on said base, a quill mounted within said housing forlongitudinal, non-rotary movement relative thereto, and a rotationalsystem mounted in said quill and including a spindle adapted forrotational movement within said quill, the improvement comprising: a. apair of longitudinally spaced-apart specimen treating means mounted onsaid spindle adjacent one end thereof; b. a sliding cross slide platemounted on said support base and designed to be moved both toward andaway from said specimen treating means; c. a specimen holder removablymounted on said cross slide plate and designed to bring one or morespecimens into contacting engagement with said sPecimen treating means;and d. means for effecting accurate longitudinal movement of saidspindle, said means comprising a differential screw having a firstannular member with internally and externally threaded portions, thelead of said externally threaded portion being different than the leadof said internally threaded portion and a second member with aninternally threaded portion, the internal threads of said second memberbeing disposed in complimental engagement with the external threads ofsaid first member, and a portion of said quill being externallythreaded, the external threads of said quill being disposed incomplimental engagement with the internal threads of said first member,and said differential screw also including an annular dial means mountedfor rotational movement with said first member.
 7. In a machine forproducing thin section specimens, said machine including a support base,a quill housing mounted on said base, a quill mounted within saidhousing for longitudinal, non-rotary movement relative thereto, and arotational system mounted in said quill and including a spindle adaptedfor rotational movement within said quill, the improvement comprising:a. a pair of longitudinally spaced-apart specimen treating means mountedon said spindle adjacent one end thereof; b. a sliding cross slide platemounted on said support base and designed to be moved both toward andaway from said specimen treating means; c. a specimen holder removablymounted on said cross slide plate and designed to bring one or morespecimens into contacting engagement with said specimen treating means;and d. means for effecting accurate longitudinal movement of saidspindle, said means comprising a differential screw having a firstannular member with internally and externally threaded portions, thelead of said externally threaded portion being different from the leadof said internally threaded portion, a portion of said gull housingbeing internally threaded, the internal threads of said quill housingbeing disposed in complemental engagement with the external threads ofsaid first member, and a portion of said quill being externallythreaded, the external threads of said quill being disposed incomplemental engagement with the internal threads of said first member,and said differential screw also including an annular dial means mountedfor rotational movement with said first member.
 8. In a machine asdescribed in claim 6 above in which said second member is mounted onsaid quill housing.
 9. In a machine as described in claim 6 aboveincluding means for sensing and indicating the relative amount oflongitudinal movement of said spindle, said means including a first partsecured to said quill housing and including an indicating member and ascale member, and a second part one portion of which is disposed totransmit longitudinal movement of said spindle to the indicating meansof said first part.
 10. In a machine as described in claim 6 aboveincluding means for sensing and indicating the relative amount oflongitudinal movement of the specimen treating means, said meansincluding a first part secured to said quill housing and including anindicating member and a scale member, and a second part comprising asensor rod mounted within said quill housing for reciprocal movementrelative thereto, said sensor rod being biased in a direction toward anadjacent surface of said specimen treating means, said sensor rod havinga portion thereof disposed in motion transmitting engagement with theindicating means of said first part whereby longitudinal movement ofsaid specimen treating means may be transmitted to the indicating memberof said first part.
 11. A machine for producing thin section specimenscomprising: a. a support base; b. a quill housing mounted on said base;c. a quill mounted within said housing for longitudinal, non-rotarymovement relative thereto; d. a rotational system mounted within saidquill, saiD system having a spindle adaptable to rotational movement,and a pair of longitudinally spaced-apart specimen treating meansmounted on said spindle adjacent one end thereof; e. a power meansmounted on said support base adjacent said rotational system anddesigned to transmit rotational power to said spindle; f. a slidingcross slide plate mounted on said support base and designed to be movedboth toward and away from the specimen treating means of said rotationalsystem; g. a specimen holder removably mounted on said cross-slide plateand designed to bring one or more specimens into contacting engagementwith said specimen treating means when said cross slide plate is movedtoward said rotational system; h. means for effecting accuratelongitudinal adjustment of said spindle, said means comprising adifferential screw, said screw having internally and externally threadedportions, the lead of said externally threaded portion being differentthan the lead of said internally threaded portion, and including (i) anannular micrometer dial, (ii) said quill housing having fixed internalthreads, the internal threads of said quill housing being disposed incomplemental engagement with the external threads of said differentialscrew, and (iii) a portion of said quill including an externallythreaded portion, the external threads of said quill being disposed incomplemental engagement with the internal threads of said differentialscrew; and i. means for sensing and accurately indicating the relativeamount of longitudinal movement of said spindle, said means including(i) a first part secured to said quill housing and including anindicating member and a scale means, and (ii) a second part one portionof which is disposed to transmit longitudinal movement of said specimentreating means to the indicating means of said first part.